It has been known for many years to pour concrete walls by placing panels in an upright fashion and spaced apart, and to place liquid concrete between them. Such concrete walls have, for example, been used as basement walls for homes. However, very often, interior load bearing walls have been formed of the more usual concrete block placed on footings in the usual manner. More recently, however, there has been considerable emphasis on the use of poured concrete in the construction of large-- usually high-rise-- buildings such as apartment buildings. Such construction has very often employed the placement of poured concrete floors and formed columns or block or brick walls. More recently, however, it has been felt desirable to pour the concrete walls as well as the floors, and this has necessitated the development of concrete forming structures which are particularly intended for use during the formation of concrete walls as they are being poured and are setting.
Because of the different problems which are encountered--particularly the problems of developing and maintaining concrete forming structures having entirely different load bearing requirements and characteristics-- there has very often been a separate contracting arrangement for the construction of high-rise buildings in respect of the horizontal forming (the floors) and the vertical forming (the walls).
There has, however, developed a system or approach to the construction of large buildings using poured concrete techniques whereby the concrete forming structures-- the forms-- are "flown" or placed in position using overhead cranes which may either be of the self climbing or mobile variety. This has been made particularly possible due to the development of concrete forming structures of the sort taught in Peter J. Avery Canadian Pat. No. 941,138 issued Feb. 5, 1974, wherein horizontal panels are carried and secured to top-hat beams of extruded aluminum, which in turn are secured through bolts placed in bolt slots within the beams so that the beams are secured to trusses, also formed of extruded aluminum. It has also been desirable to fly wall forms in large panels, or indeed as completed wall forms where the two spaced and opposed panels are moved as a unit. Previously, such as referred to in Peter J. Avery U.S. Pat. No. 3,899,152 issued Aug. 12, 1975, wall panels were devised using beams of the sort referred to in that patent and using steel channel members as the supporting and strengthening structure. For a number of reasons, particularly strength per unit weight and the number of ties required it was felt desirable to eliminate the use of steel channel members and to replace them with extruded aluminum members if possible. More especially, however, it was also felt desirable to develop strongback members for use in wall forming structures such that the studs-- to which the sheathing, which comprises the face against which the concrete is formed, is secured-- may be secured or attached to the strongbacks at any position without the necessity for drilling holes or special placements, and merely by using clamping members secured to the studs. This is particularly possible when the studs are top-hat beams of the sort referred to in Peter J. Avery Canadian Pat. No. 990,481 issued June 8, 1976 or the equivalent U.S. Pat. No. 3,899,152 issued Aug. 12, 1975, each being assigned to a common assignee herewith. In particular, it was felt to be most desirable to eliminate the necessity at any time to place holes, either in the shop or in the field, through the strongback members for purposes of attachment of the studs to the strongbacks, because the placement and machining of the holes is expensive, they reduce the strength of the strongbacks, and they are limiting as to the spacing which may then be permitted for the studs. At the same time, it was also felt desirable to provide strongback members such that additional or accessory attachments such as catwalk brackets, wall plumbing or wall bracing attachments, and the like might be secured to the strongbacks; as well as to provide for placement through the cavity into which the liquid concrete would be placed of as few tie members as possible but with the adaptability to place those tie members at any desired location and in such a manner that the forces exerted by the tie members as they take up the liquid pressure of freshly poured concrete would be transmitted to the strongback members without localized failure or undue local stresses being caused in the material of the strongback members.
Thus, this invention provides a wall forming structure which is intended for use during the construction of poured concrete walls, where the wall forming structure comprises a pair of opposed panels which are spaced apart so as to provide a cavity into which fluid concrete is placed so as to form the wall, and where each panel comprises substantially planar sheathing secured to a plurality of studs which are placed substantially parallel one to another. The studs are secured to at least a pair of strongbacks which are placed perpendicularly to the studs, and by this arrangement the panels are thereby capable of being moved as an integral unit. A plurality of ties extends through or across the cavity and through the sheathing from a strongback of one of the opposed panels to a strongback of the other opposed panel. In the wall forming structure of the present invention, each strongback comprises a pair of channel-shaped members which are placed in spaced back-to-back relationship; and each channel-shaped member has a pair of side walls and a base, an outwardly facing T-shaped slot suitable for receiving the head of a bolt in each side wall near the base, and an inwardly facing flange at the end of each side wall remote from the base. A plurality of plates each having an opening through its thickness is secured to each pair of channel-shaped members-- i.e., to each strongback-- by bolts placed in the T-shaped slots in the side wall of each of the channel-shaped members on the side thereof remote from the sheathing, with the openings in the plates being positioned between the respective channel-shaped members so that a tie may pass between the opposed bases of the pair of channel-shaped members and extend through the respective opening in the respective plate.
For purposes of this specification, as will be noted hereafter, it is assumed that either the studs or the strongback members may be placed in either a horizontal or vertical orientation. The sheathing is secured to the studs, and the studs are secured to the strongbacks which are outside the studs with respect to the cavity into which the liquid concrete is placed. Historically, when concrete wall forming structures were comprised entirely of wooden structural members, a plurality of vertical studs on very close centres were placed behind the sheathing, and horizontal waler members were thereafter placed behind the vertical studs. By so doing, the stud spacing could be constant. However, as will appear hereafter, it is more general, particularly according to this invention, to use vertical strongback members behind horizontal studs which are not equally spaced from top to bottom.
In general, it is the contemplation of this invention that each of the studs would comprise a top-hat beam which is generally of the sort referred to above. Each such top-hat beam has a top-hat channel with a pair of outwardly extending flanges and an insert in said channel in which driveable fasteners may be driven so as to secure the sheathing to the studs. A web portion extends away from the top-hat channel, and a base portion having a T-shaped slot suitable for receiving the head of a bolt is formed in the base portion of the top-hat beam, with a pair of base flanges extending outwardly from the T-shaped slot. The studs may thus be secured to the strongbacks-- i.e., to the channel-shaped members which form the strongbacks-- by clamps which are secured to the studs by bolts having their heads placed in the T-shaped bolt slots of the top-hat beams, where the clamps have a hook-like end which is adapted to fit over the inwardly facing flanges of the side walls of the channel-shaped members which comprise the strongbacks at the sides thereof which are contiguous to the studs.
It is also contemplated that, in general, the studs and strongbacks would all be extruded aluminum members, which provides the best combination of strength per unit weight, so that very large panels may be flown at one time.
By using the top-hat beam referred to above, a common component of wall forming or slab forming structures is used, especially on job-sites where concrete forming structures of the sort taught in the Avery patents referred to above are used. It is also anticipated that, by using a splice member which is referred to hereafter, the strongback members may be extended to any desired length. Where the splice members are to be used, holes are placed in the base of the channel-shaped member and in the base of the splice member, according to construction industry standards, and the strength of the strongback member at that point is thereby still within acceptable limits. In any event, those are the only holes contemplated to be drilled in any of the studs or strongback members, and are used only to extend the length of the strongback members and not to secure other members such as studs to the strongback members.
Plates were referred to above, and are secured to the strongbacks in such a manner that a single plate is secured to each of the pair of back-to-back channel-shaped members which form the strongback so that the ties which take up the outward pressure of the newly placed liquid concrete are secured in place by passing between the back-to-back channel members and through a hole which is in the plate and through the thickness thereof, for that purpose. Sometimes, however, it is desired to use ties having different diameters, depending upon the thickness and/or height of the wall; and for that purpose, the plates are normally provided having a large diameter hole so as to accommodate the largest contemplated tie, and with an insert plate-- in this case, usually steel-- which may be placed over the hole and which in turn has a smaller hole formed therein.
It has also been a problem, in the field, of preventing slippage of one or another of a pair of back-to-back steel channels as they may be being assembled, or indeed flown. This invention contemplates the use of a "shoe" which is generally L-shaped and adapted to have one leg of the L extend across the ends of the channel-shaped members. The shoe is also adapted to be secured to the channel-shaped members of the strongbacks by bolts having their heads placed in the T-shaped slots which are formed in the strongback channel-shaped members.